[Rambolleja]

Hey guys,

2 weeks ago I ordered a Lambda 6.03 precision inner barrel for my VSR-10, from Powair6.

I'm really into airsoft thinkering, etc. I checked the inner barrel on our machining company's CMM granite table, which is a 100% quality flat surface, the inner barrel (out of the box) is bent. I attached an image, if I put the barrel on the table like this, the bent seems like the red curve, the space under the barrel is like <0,1mm, but it's there. I can see the light coming throught the gap. I tried on the other side of the table, same result. I rotated the barrel by 180°, the curve also rotates with it, so to the table is OK, the barrel is bent.

The interesting part is, I have 4 used inner barrels (Maple leaf crazy jet, stock vsr barrel, PDI etc), some are like 2-3 months old, some are 2 years old, both are bent like this way. My outer barrel is also bent like this.

I'm not complaining about the quality, I'm just curious, that am I missing something? The bent is meant to be there, or it should be as straight as possible?

 

[mrpugster]

Should be straight as possible but <0.1mm isn't really a problem. To achieve 99.9999999% straightness I'd imagine that Lamda would cost a great deal more. You're in the UK right?

 

[Sodium]

Yeah it's really really really hard to make a precise barrel like that without a tiny bit of bend.

 

[Rambolleja]

Should be straight as possible but <0.1mm isn't really a problem. To achieve 99.9999999% straightness I'd imagine that Lamda would cost a great deal more. You're in the UK right?

I see, thank you. No, I live in Hungary.

 

[Rambolleja]

Yeah it's really really really hard to make a precise barrel like that without a tiny bit of bend.

I see, okay, thank you!

 

[Plazmaburn]

From what I understand from the process used to make barrels, most of them start life on a large spool and goes through a machine process to straighten them and machine them out.

There are some ways to straighten them afterwards, but you need to be careful if you try it as you can crush the barrel instead of straighten it.

It should be as straight as possible, but airsoft is not a high precision, minimal tolerance sport. We are shooting spheres at one another which are, from a ballistic point, some of the worst shapes to use.

 

[Whamhammer]

I am not sure about all of the process steps in which inner barrels are made, it can certainly stand that there are going to be some degree of tolerances that are allowable for quality acceptances. Yes, the tolerances aren't as likely tight as actual rifle barrel manufacturing, as it is a low strain, airsoft barrel, but there should still be some tolerances.

One thing I am curious on is when is the bore being created? If it is created from a solid metal core, unwound from a spool and then bored AFTER its straightened out, a very minor bend, that did not get created AFTER the bore was done may not be so much of an issue PRESUMING the bore was entirely straight on the inside as well as both end and the hop window.

All things considered equal, I would believe that a stronger metal (like stainless steel vs brass or aluminum), and a narrower bore (presuming the exterior is a ~constant in airsoft inner barrels < I think this is the case>), would tend to be more "straight" due to a stiffer item making a lower probability of bending during handling once the manufacturing process and QA is completed.

 

[Plazmaburn]

I'm fairly sure that it's "thick wall tubing" and the bore is finished towards the end of the process. Also depends on the process. PDI used to make their barrels with a cold hammer process,( which has been questioned if it's true and if it really matters, tl:dr they did, and sort of. ) Then reamed and lapped. (Again, varies and could be wrong)

 

[Whamhammer]

I'm fairly sure that it's "thick wall tubing" and the bore is finished towards the end of the process. Also depends on the process. PDI used to make their barrels with a cold hammer process,( which has been questioned if it's true and if it really matters, tl:dr they did, and sort of. ) Then reamed and lapped. (Again, varies and could be wrong)

If that is the case, I guess that it comes down how much more it gets bored-out by, but I am sure that even a few hundredths would be enough to guarantee a straight bore from end to end.

 

[Plazmaburn]

In theory the ream alone would straighten the bore completely. Literally the reams job. But! That is assuming they actually ream the barrels at all. I have seen some pretty wavy inner barrels that would suggest they don't.

I doubt that they are deep boring barrels. Just the tooling of that size would drift too much. WireEDM would work, but cost prohibitive.

 

[SiliconeSword]

I've used my grandfather's granite block for visual inspection and some V blocks+dial indicator to check straightness, and barrels vary widely.

In your situation you're probably fine to try straightening it after finding the exact places it needs to be bent. For anybody without access to a granite surface block or maybe a milling machine's bed this probably shouldn't be attempted.

 

[Whamhammer]

I've used my grandfather's granite block for visual inspection and some V blocks+dial indicator to check straightness, and barrels vary widely.

In your situation you're probably fine to try straightening it after finding the exact places it needs to be bent. For anybody without access to a granite surface block or maybe a milling machine's bed this probably shouldn't be attempted.

I guess the biggest question is does the outer "bend/curve" actually impact the performance of the barrel? If the bore is straight, I would thing that it wouldn't, unless the bend interferes the muzzle direction.

 

[SiliconeSword]

I guess the biggest question is does the outer "bend/curve" actually impact the performance of the barrel? If the bore is straight, I would thing that it wouldn't, unless the bend interferes the muzzle direction.

I imagine that it probably does, I feel like the wall thickness is consistent enough that you'd see that.
Back in the day people ran LRBs that were basically just an upwards bent barrel, but I can't imagine a side bend would make your BBs any straighter than without

 

[Whamhammer]

I imagine that it probably does, I feel like the wall thickness is consistent enough that you'd see that.
Back in the day people ran LRBs that were basically just an upwards bent barrel, but I can't imagine a side bend would make your BBs any straighter than without

The thing is that from of the OP showed, the center has the curve but the further out it goes, the more "level" the barrel is. I presume this is to do with the notion that the barrel material is metal line on a spool (as was discussed before). If there is a cleanup ream-bore cleanup run once the barrel is "straightened", the slight bend on the outside wouldn't be an issue, especially since the barrel crowning, hop window porting and other cuts are made after the fact.

I know the barrels that you are speaking of, and if I remember, it was pretty much on the muzzle end that received the bend.

Funnily enough, the Germans in WWII tried a bent barrel on some STG 44's as a "Krummlauf" model but bent downwards (alongside a periscope) to allow a shooter to shoot from behind a wall or other hard cover to "snipe" people, similar idea, different principles of physics. The result was not very successful, the same result as the bent airsoft barrel concept.

 

[Plazmaburn]

Barrel spacers are a thing and would fix that. Sort of. Won't do much to the outer barrel, but the inner it will.

 

[Whamhammer]

I will also say that I have had more problems with crappy/bent scope rings or scratched barrel crowns impacting my shooting than a bent barrel.

 

[Plazmaburn]

Bad rails, bad scope rings and bad barrel crowns are way more impacting then a slightly bent inner barrel. And those are probably more common.

 

[Ivan B Creepin]

Bad rails, bad scope rings and bad barrel crowns are way more impacting then a slightly bent inner barrel. And those are probably more common.

Oh man, how would you even know?

 

[Plazmaburn]

Rails are difficult to really know if they're good or not. Requires a lot of measurements and a few different rifles. Having a VSR-X makes testing stuff a lot easier as it's 100% straight with zero wiggles or moves. I've also added registration points in numerous locations to make testing parts on it easy. It's also made out of 4140. So it gives no fucks about a lot of things that would normally wreck a normal airsoft rifle.

Scope rings are easier to tell. There are videos about how to tell and test. Mostly if you look at your rifle from the top if your scope is not aligned with your barrel then odds are good it's your scope rings. Also a lot of rings are not centered above the rail. They are off center.

Barrel crowns are easy. Look at the end, if it's not even all the way around, then it's shit.

 

[Whamhammer]

Oh man, how would you even know?

Well, the worst one that I experienced was a time where I no matter what I did, it seemed that the shots that would hit a target at 100 feet would always be somewhat off to the left and up at 200 feet or greater distance; I couldn't adjust the scope to compensate. I tried a one-piece scope mount and it shot straight as an arrow.
The ring assembly seemed to have been bent right and down when they were made.